1. Field of Invention
The present invention belongs to image-processing field, relates to a text image processing method, and especially relates to a text image trimming method.
2. Description of Related Arts
Digital Camera (DC) is becoming more and more popular these years, at present, built-in DC is standard feature of a cellphone. These digital imaging devices are often used to shoot text images. Text image means the image contains one or more lines of printed text, such as image of a business card, a menu, a bill or a note .etc. The image taken by DC is different from that scanned by scanner, the differences includes, for example, that the image taken by DC is less clearer, the image taken by DC could be distortional because of the projection deformation of the subject such as business card, and the images taken by DC could also contain content or background other than the desired subject. Because of shooting habits or framing demands, the text image shot by user usually contains background, while what is needed is the text image without the background, just like the image scanned by a scanner.
There have been applications that can separate text image from its background, for example, the mobiReader, a business card editing software from the Apple's app store. It defines a preview area, and requires that user put the business card right in the preview area before shooting to obtain an image that only contains the content of the business card, then the effect of trimming can be achieved. However, this is a manual trimming method. There are other applications, such as the genius Scan from the Apple's app store, that can gain text region by using straight line detection method in image processing field because the shapes of the text images, for example, images of business cards, menus, bills or notes, are quadrangle with clear edge.
But when the text contains straight lines, the above-mentioned method may recognize the straight lines in the text as the edge of the text by mistake. With regards to this kind of images, other certain clues can be helpful to gain text image area, increase the accuracy of detecting the text region, and guarantee the trimming effect.
Regardless of whether a text image was taken by DC or scanned by a scanner, existing software, such as business-card-recognizing software or OCR software in the scanner, can detect and recognize the text in the text image.